Tunica layers of the carotid artery of the rat: isolation and macromolecular synthetic abilities.

The tunicas media and adventitia can be isolated, intact, from the rat carotid artery by simple mechanical extrusion. While morphologically normal, when incubated for 24 hr in vitro in appropriate radioactive precursor the isolated layers synthesized DNA, RNA and protein at very low levels which was only a fraction (5-15%) of that synthesized by the intact vessel.